bsdcat

bsdcat_tbd.c

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <err.h>
#include <fcntl.h>
#include <sys/stat.h>

void cat(int rfd) {
    int wfd;
    static char *buf;

    static size_t bsize;

    struct stat sbuf;

    wfd = fileno(stdout);

    if (fstat(wfd, &sbuf))
        err(1, "stdout");

    bsize = sbuf.st_blksize;
    buf = malloc(bsize);
    if (!buf)
        err(1, 0);

    ssize_t nr, nw;

    int offset = 0;

    nr = read(rfd, buf, bsize);

    while (nr > 0) {
        for (offset = 0; nr > 0; nr-=nw, offset += nw) {
            nw = write(wfd, buf, nr);
            if (nw < 0)
                err(1, "stdout");
        }
    }
    nr = read(rfd, buf, bsize);
}

int main(int argc, char *argv[]) {

    // the first element of argv is the command itself
    ++argv;
   
    int fd;
    fd = fileno(stdin);
    while (*argv) {
        // do the thing
        fd = open(*argv, O_RDONLY);

        if (fd < 0)
            err(1, "%s", *argv);
        // show content of the file

        ++argv;
    }
    return 0;
}